An image sensor is being developed to reduce a pixel size in association with increase in the number of pixels. On the other hand, development to shoot images at high speed and to improve moving picture characteristics is also being promoted. In this way, when pixels are reduced in size or shooting is performed at high speed, the number of photons entering one pixel is reduced, which lowers sensitivity.
Further, in a field of a monitoring camera, a camera capable of shooting pictures in a dark place is desired. In other words, a highly sensitive sensor is necessary.
With respect to such demands, there is reported that a compound semiconductor of a p-type chalcopyrite structure is applied, as a photoelectric conversion film high in optical absorption coefficient, to an image sensor to achieve high sensitivity (for example, refer to PTL1, PTL2, and PTL3).